Toxicological effects of graphene on mussel Mytilus galloprovincialis hemocytes after individual and combined exposure with triphenyl phosphate

Comparative assessment of silver nanoparticle and silver nitrate toxicities in Mytilus galloprovincialis

Silver nanoparticles (AgNPs) and Ag+ ions are both detected in aquatic environments, posing potential risks to marine ecosystems. Mytilus galloprovincialis is an effective model for monitoring marine environments. In this study, AgNPs were synthesized using a chemical approach, and to distinguish the toxicological effects of AgNPs and AgNO3 in M. galloprovincialis, experiments were conducted using various treatments (control, AgNO3, AgNPs, and AgNPs + cysteine). Our findings revealed that the uptake rate of AgNPs and AgNO3 was different, they predominantly accumulated in the hepatopancreas and gills. qRT-PCR analysis showed varying degrees of alterations in immune genes of HSPA12A, TCTP, sHSP22, sHSP24.1, P63, Bcl-2, and Ras. Histopathological analysis demonstrated disrupted epithelial cell arrangements and connective tissue damage in the hepatopancreas, with the AgNPs exhibiting the most severe damage compared to AgNO3. In addition, AgNPs significantly induced oxidative stress in hemocytes compared to AgNO3, resulting in elevated apoptosis rates. These findings contribute to a deeper understanding of the AgNPs and AgNO3 interactions in marine environments and provide a theoretical basis for the evaluation of marine pollution and biomonitoring strategies.

Joint Toxicity and Interaction of Carbon-Based Nanomaterials with Co-Existing Pollutants in Aquatic Environments: A Review

This review paper focuses on the joint toxicity and interaction of carbon-based nanomaterials (CNMs) with co-existing pollutants in aquatic environments. It explores the potential harmful effects of chemical mixtures with CNMs on aquatic organisms, emphasizing the importance of scientific modeling to predict mixed toxic effects. The study involved a systematic literature review to gather information on the joint toxicity and interaction between CNMs and various co-contaminants in aquatic settings. A total of 53 publications were chosen and analyzed, categorizing the studies based on the tested CNMs, types of co-contaminants, and the used species. Common test models included fish and microalgae, with zebrafish being the most studied species. The review underscores the necessity of conducting mixture toxicity testing to assess whether the combined effects of CNMs and co-existing pollutants are additive, synergistic, or antagonistic. The development of in silico models based on the solid foundation of research data represents the best opportunity for joint toxicity prediction, eliminating the need for a great quantity of experimental studies.

Abnormality of mussel in the early developmental stages induced by graphene and triphenyl phosphate: In silico toxicogenomic data-mining, in vivo, and toxicity pathway-oriented approach

Increasing number of complex mixtures of organic pollutants in coastal area (especially for nanomaterials and micro/nanoplastics associated chemicals) threaten aquatic ecosystems and their joint hazards are complex and demanding tasks. Mussels are the most sensitive marine faunal groups in the world, and their early developmental stages (embryo and larvae) are particularly susceptible to environmental contaminants, which can distinguish the probable mechanisms of mixture-induced growth toxicity. In this study, the potential critical target and biological processes affected by graphene and triphenyl phosphate (TPP) were developed by mining public toxicogenomic data. And their combined toxic effects were verified by toxicological assay at early developmental stages in filter-feeding mussels (embryo and larvae). It showed that interactions among graphene/TPP with 111 genes (ABCB1, TP53, SOD, CAT, HSP, etc.) affected phenotypes along conceptual framework linking these chemicals to developmental abnormality endpoints. The PPAR signaling pathway, monocarboxylic acid metabolic process, regulation of lipid metabolic process, response to oxidative stress, and gonad development were noted as the key molecular pathways that contributed to the developmental abnormality. Enriched phenotype analysis revealed biological processes (cell proliferation, cell apoptosis, inflammatory response, response to oxidative stress, and lipid metabolism) affected by the investigated mixture. Combined, our results supported that adverse effects induced by contaminants/ mixture could not only be mediated by single receptor signaling or be predicted by the simple additive effect of contaminants. The results offer a framework for better comprehending the developmental toxicity of environmental contaminants in mussels and other invertebrate species, which have considerable potential for hazard assessment of coastal mixture.

A multibiomarker approach to assess the ecotoxicological effects of diclofenac on Asian clam Corbicula fluminea (O. F. Müller, 1774)

Diclofenac (DCF), one of the most current and widely used nonsteroidal anti-inflammatory drugs (NSAIDs), has been frequently detected in aquatic environments worldwide. However, the ecotoxicological effects of DCF on freshwater invertebrates remain largely unknown. In the present study, Corbicula fluminea were exposed to environmentally relevant concentrations of DCF (0, 2, 20, and 200 μg/L) for 28 days, and the potential adverse effects of DCF on siphoning behavior, antioxidant responses, and apoptosis were investigated. Our results showed that the siphon efficiencies of clams were significantly suppressed under DCF stress. DCF exerted neurotoxicity via reducing the activity of acetylcholinesterase (AChE) in gills and digestive gland of C. fluminea. Exposure to DCF induced antioxidant stress and increased malondialdehyde (MDA) levels in both gills and digestive gland of C. fluminea. Transcriptional alterations of apoptosis-related genes indicated that DCF might induce apoptosis by triggering mitochondrial apoptotic pathway. These findings can improve our understanding of the ecological risk of DCF in freshwater ecosystems.

Fate and effects of graphene oxide alone and with sorbed benzo(a)pyrene in mussels Mytilus galloprovincialis

Graphene oxide (GO) has gained a great scientific and economic interest due to its unique properties. As incorporation of GO in consumer products is rising, it is expected that GO will end up in oceans. Due to its high surface to volume ratio, GO can adsorb persistent organic pollutants (POPs), such as benzo(a)pyrene (BaP), and act as carrier of POPs, increasing their bioavailability to marine organisms. Thus, uptake and effects of GO in marine biota represent a major concern. This work aimed to assess the potential hazards of GO, alone or with sorbed BaP (GO+BaP), and BaP alone in marine mussels after 7 days of exposure. GO was detected through Raman spectroscopy in the lumen of the digestive tract and in feces of mussels exposed to GO and GO+BaP while BaP was bioaccumulated in mussels exposed to GO+BaP, but especially in those exposed to BaP. Overall, GO acted as a carrier of BaP to mussels but GO appeared to protect mussels towards BaP accumulation. Some effects observed in mussels exposed to GO+BaP were due to BaP carried onto GO nanoplatelets. Enhanced toxicity of GO+BaP with respect to GO and/or BaP or to controls were identified for other biological responses, demonstrating the complexity of interactions between GO and BaP.

Review: Mytilus galloprovincialis: An essential, low-cost model organism for the impact of xenobiotics on oxidative stress and public health

The level of pollution becomes more and more of a pressuring matter for humankind at a worldwide level. Often the focus is on the effects that we can directly and see such as decreased air quality and higher than normal temperatures and weather, but the effects we cannot see are frequently overlooked. For at least the past decade increasing importance has been given towards the effects of pollution of living animals or non-target organisms and plants. For this purpose, one model animal that surfaced is the purpose, one model animal surfaced is Mytilus galloprovincialis. As all mussels, this species is capable of bio-accumulating important quantities of different xenobiotics such as pesticides, paints, medicines, heavy metals, industrial compounds, and even compounds marketed as antioxidants and antivirals. Their toxic effects can be assessed through their impact on oxidative stress, lysosomal membrane stability, and cell viability through trypan blue exclusion test and neutral red retention assay techniques. The purpose of this paper is to highlight the benefits of using M. galloprovincialis as an animal model for toxicological assays of various classes of xenobiotics by bringing to light the studies that have approached the matter.

Effects of polystyrene and triphenyl phosphate on growth, photosynthesis and oxidative stress of Chaetoceros meülleri

The toxicity of microplastics to marine organisms has attracted much attention; however, studies of their effects on marine microalgae remain limited. Here, the effects of the single and combined toxicity of polystyrene (PS) and triphenyl phosphate (TPhP) on the cell growth, photosynthesis, and oxidative stress of Chaetoceros meülleri were investigated. PS inhibited growth of the algae cells and caused a dose-dependent effect on oxidative stress. The significantly high production of reactive oxygen species (ROS) induced severe cell membrane damage, as confirmed by high fluorescence polarization. However, there was no obvious decrease in chlorophyll a content, and 80 mg/L of PS significantly promoted chlorophyll a synthesis. The TPhP also inhibited cell growth, except at low concentrations (0.2-0.8 mg/L), which stimulated algae growth over 48 h. Moreover, no obvious decrease in chlorophyll a and maximal photochemical efficiency of PSII was found in the TPhP experimental groups except for 3.2 mg/L TPhP, where the rapid light curves showed a significantly reduced photosynthetic capacity of algae. In addition, TPhP caused high ROS levels at 96 h, resulting in cell membrane damage. Using the additive index and independent action methods, the combined toxic effects of PS and TPhP on the algae were evaluated as antagonistic; however, cell membrane damage caused by high ROS levels was still noticeable. This study has shown the potential toxicity of PS and TPhP to marine microalgae, and provided insights into the combined risk assessment of TPhP and microplastics in the marine environment.

New insights into the mechanism of hepatocyte apoptosis induced by typical organophosphate ester: An integrated in vitro and in silico approach

Apoptosis is one of the typical features of liver diseases, therefore molecular targets of hepatic apoptosis and regulatory mechanisms need to be further investigated. The caspases play important functions in the execution of apoptosis and many studies have focused on classical caspase-dependent cell death pathways. However, other types of cell death pathways (such as mitochondrial poly (ADP-ribose) polymerase-1 (PARP1) pathway) are suggested to be also as important as the caspase-mediated pathways in reflection of early toxic effects in hepatocytes, which requires additional research. In this work, an approach integrated in silico and in vitro was used to investigate the underlying toxicological mechanisms of hepatocyte apoptosis through the PARP1 dependent cell death pathway induced by triphenyl phosphate (TPP). Docking view showed that TPP could interact with helix αJ to affect the activation of PARP1 as a molecular initial event. In vitro assays suggested some biochemical events downstream of PARP1 activation, such as mitochondrial injury, apoptosis inducing factor (AIF) release, reactive oxygen species (ROS) production, and DNA damage. Moreover, the apoptosis was alleviated when cells were pretreated with PJ34 hydrochloride (PARP1 inhibitor), suggesting the mitochondrial PARP1 dependent pathway played a pivotal role in L02 cells apoptosis. This study indicated that PARP1 was an important molecular target in this process. And it also helped to understand the mechanism of hepatocytes apoptosis, early hepatic toxicity, and even liver diseases.

Microplastics aggravate the adverse effects of BDE-47 on physiological and defense performance in mussels

The highly hydrophobic surfaces make microplastics a potential carrier of organic pollutants in the marine environment. In order to explore the toxic effects of polybrominated diphenyl ethers (BDE-47) combined with microplastics on marine organisms, we exposed the marine mussel Mytilus coruscus to micro-PS combined with BDE-47 for 21 days to determine the immune defense, oxidative stress and energy metabolism of the mussels. The results showed that the clearance rate (CR) of mussels exposed to single micro-PS, single BDE-47 or both was lower than control group. In general, compared to single BDE-47 exposure, the combination of micro-PS and BDE-47 significantly increased respiration rate (RR), activities of acid phosphatase (ACP) and alkaline phosphatase (ALP), reactive oxygen species (ROS) production and malondialdehyde (MDA) concentrations, but significantly decreased lactate dehydrogenase (LDH) activity and the relative expression of heat shock protein (Hsp70 and 90). Overall, combined stress has more adverse effects on defense performance and energy metabolism in mussels and micro-PS seem to exacerbate the toxicological effects of BDE-47. As microplastics pollution may deteriorate in the future, the health of mussels may be threatened in organically polluted environment, which eventually change the stability of the structure and function of intertidal ecosystem.